Rupture discs provide a relatively inexpensive means for protecting pressure systems from overpressure, especially when compared to pressure relief valves of the same accuracy in tripping at a selected overpressure. However, once a rupture disc has ruptured, it must be replaced before the pressure vessel can be pressurized again. In most installations, this involves the time consuming removal of pipe flanges, removal and replacement of the spent rupture disc assembly, replacement of the pipe flanges, and tightening of nuts and bolts thereof to specified torque. In order to expedite the replacement of rupture discs, preassembled rupture disc arrangements have been provided in which the rupture disc is sandwiched between a pair of seating or sealing rings which are bolted or welded together either by the manufacturer or in the maintainence shop of the plant in which the disc is employed. However, with most such disc assemblies, it is still necessary to remove and replace the pipe flanges between which the assembly is installed. Such disassembly and reassembly of the pressure relief vent requires that man hours be expended; and, more importantly, the pressure vessel remains inoperative during such repair.